function User(name) {
  this.name = name;
}
User.prototype = {
  show: function() {}
};

let hd = new User("后盾人");
let xj = new hd.constructor("向军");
console.log(hd.constructor == User, hd.constructor)
console.log(xj); //String {"向军"}
console.log(new Object("阿勇"))
